Equipment Specs


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Agricultural Equipment
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2003 Dragone 280VPS Power Harrow
A harrow is a cultivating or tillage tool used in agriculture consisting of a wooden or metal frame with spike-like or spring action teeth, discs or sharp projecting teeth called tines used to pulverize and smooth surface soils. Harrowing typically occurs after a field is plowed to break large lumps or clods of soil, provide a finer finish or good tilth, ideal for the reception of seeding.

The implement may be used for other agricultural tasks that include the preparation of seedbeds, the covering of seeds, destroying weeds, and the aeration of pastures. Harrows of many types and sizes exist to carry out these various functions. The three most common types of harrows are disc, tine, and chain.


[edit] History

[edit] The Bush Harrow

The harrow has been around as long as the plow. Some of the first harrows date back to the time of the Egyptians and were archaic at best but served a general purpose. In its most common and widely used form, the first harrow, known as a bush harrow, was nothing more than a bough of twiggy branches or thorny bushes attached to some sort of a wooden frame.[1] For instance, the Egyptians used a bush harrow made from dried palm leaves. In his book, 300 Years of Farm Implements and Machinery, Ronald Stokes Barlow notes that bush harrow had a surprisingly long run through history, well up until the 1880s when it was primarily used to cover seeds in certain geographic areas.[2] In parts of the world today archaic versions of the harrow still exist. In India, a harrow is still used, consisting of a ladder-like apparatus constructed of bamboo.[3]

2005 Yetter 3546 46 ft. Flat Fold Rotary Hoe

[edit] Early Harrow Prototypes

By the 1880s, a number of different harrows were being employed. The most common form was a simple smoothing harrow with iron teeth fixed either to a wooden or iron framework. The teeth were adjustable to be set at different angles so that penetration at various depths into the soil was likely achievable.[4] However, rudimentary adaptations of harrows with iron or wooden teeth and fashioned to a wooden frame had well existed as far back as the Roman era. In his book, Farm Tools through the Ages, Michael Partridge cites that the Romans used a harrow constructed of a long wooden plank or log and fitted with spikes on the underside to pull roots, clean up weeds in land that had been freshly plowed.[5] These actions reflect the general function of the harrow even to this day.

During the 10th century, the harrow was already a widely used farming implement. It most likely would have been a low square or rectangular open frame platform comprised of wooden beams and supported on iron or wooden tines. Partridge argues that these early versions of the harrow were clumsy; when drawn in a straight line and pulled by oxen, the harrow was beyond controlling, often veering out of line and climbing out from the soil. A weight, such as a log or stone, would likely have been placed on the topside of the apparatus.[6] It was in the Middle Ages, that the brake harrow originated. This strong, hardy device was used for breaking up land in the winter and had a square, rectangular, or rhomboidal shape with a framework constructed from huge timber planks and square iron tines.[7]

During the 16th century, the traditional square shape of the harrow changed when the first triangular harrow appeared. This permitted the tines to be placed in a staggered position across the framework rather than set together in regular rows. The genius behind this was that each set of tine did not proceed in the same track as the one that had come before it.[8] In the 1700s, another type of harrow emerged configured again of a heavy wooden frame often shaped like the letter A and on the underside, fitted with teeth. The frame was most often made of oak and the teeth, either hickory or iron. This early version of the harrow would be dragged across the field by oxen and used to break up clumps in the freshly plowed soil and remove surface debris.[9]

All these early versions of harrows were superseded by Armstrong’s “zig zag” harrow patented in 1839 that was comprised of iron bars and had the tines arranged in such a fashion that each had followed its own track and had a distinguished line of action.[10]

[edit] The Spring-tooth Harrow

The spring-tooth was perhaps the first harrow to be manufactured on a broad basis for the agricultural industry and initially designed for use on rocky, weed strewn surfaces. Becoming available to the market in 1877 this harrow became was popular in the eastern and central parts of the U.S. where it was used to rid fields of quack grass and other pesky weeds.[11] Its name was derived from the ability of the harrow’s teeth to spring back and release when caught on an obstruction of some kind.

[edit] The Spike-tooth Harrow

Developed in the early 19th century, the spike-tooth harrow was horse or tractor drawn and had sections of 1.1 to 1.6 yards (1 to 1.5 m) long in width with lengthy spike-like teeth mounted vertically that extended downwards and were fixed to horizontal bars.[12]

[edit] The Disc Harrow

The disc harrow was an American invention patented in 1847. The first version of the disc harrow incorporated only one set of discs. This was modified in 1854 when a second disc was added. By the 1880s, self-cleaning models with up to a dozen discs were available.[13]

[edit] How it Works

The function of a harrow is similar to that of a cultivator, except that the depth of soil penetration is not as intense. Modern day harrows are typically dragged behind a tractor using a two-point or three-point linkage, or suspended on wheels. A harrow may also have different levers to adjust the depth of penetration and pull. In addition, one or more sets of cutting apparatus per harrow may be used or two different harrows may be drawn together simultaneously to achieve the desired effect given the task being carried out.

[edit] Seed Harrow

A seed harrow is a light implement with straight, closely spaced teeth that are staggered as to prevent the teeth rear from following in the tracks left my the front row of teeth. Seed harrows are typically used for providing the final touches in the preparation of seeds beds and for covering seeds after the drill. When used for covering seeds, the harrow is typically hitched directly to the drill.

[edit] Spike-tooth Harrow

The spike-tooth is an implement that has steel spikes extending downward from the frame and is usually pulled by a tractor. Its primary function is leveling, as it does not penetrate hard ground to any depth. The teeth can be triangular, round, or square and levers allow the angle or the teeth to be adjusted in either a vertical or horizontal position.

[edit] Spring-tooth Harrow

For this type of harrow, an independent frame can be set upon wheels and a seat for the operator is mounted upon standards supported by the two frames. The teeth are usually flat steel springs of scroll form that can yield in the path of an obstacle and be furnished with removable points giving the harrow added flexibility as teeth of varying shapes and sizes can used by the same machine for different kinds of work A lever enables the operator to raise the teeth more or less, freeing the teeth from debris as well as controlling the depth of action.

[edit] Disc Harrow

John Buhler Y605TD 6 ft. Offset Disc
The disc harrow is equipped with a series of sharp metal discs that are set on an angle on one or more axles to the line of pull for maximum pulverization and can stir the ground up to a considerable depth.

Discs have evolved gradually from 10 to 12 inches (25.4 to 30.4 cm) in diameter and now vary widely in diameter from 16 to 22 inches (41 to 56 cm).[14] These discs may be solid, concave or cutaway in design. Some disc types include serrated and scalloped. The type of disc also dictates functionality and the number of discs or blades is typically multiple with 12 to 14 blades per harrow. This number of blades is common on double or tandem disc harrows.

A number of factors determine the depth of penetration on a disc harrow. These include the angle of the disc, weight of the harrow, disc sharpness, disc size, and angle on the hitch.

Today the disc harrow is commonly used after harvesting to cut up grain stubble left behind in the field. It is also employed as a tillage implement aside from the plow.

[edit] Chain harrow

The chain harrow consists of a number of square link chains that are connected by cross links and fixed to a draught-bar, with the entire implement being kept expanded by stretchers and trailing weights. It is used for leveling and spreading manure and tearing up weeds or debris.

[edit] Rotary weeder

The rotary weeder or rolling cultivator consists of narrow ground-driven spiked wheels with curved teeth that have slicing action, mounted on wheels and used to break the surface between row crops.

[edit] Power-driven Harrow

Power driven harrows similar to a rotary cultivator differ from other harrows that have been developed as an implement originally used to be pulled by animals or a tractor. The reciprocating motion of a power-driven harrow involves vibration and that the bearings work in close proximity to the soil. A power-driven rotary harrow will have, for example, an even number of rotary blades arranged in a single line with an adjacent matching line of rotary blades contra rotating. One of the advantages of the power-driven harrow is that it can be easily used in combination with other implements being hitched directly behind it such as a light seed drill. Power-driven harrow are excellent for working in deeper soils conditions.

[edit] Common Manufacturers

[edit] Additional Photos

1995 Riteway RJH8055 55 ft. Heavy Harrow
2000 Brandt 7000 Contour Commander Heavy Harrow
Blanchard Hydra-Lift 40 ft. Harrow Packer
Flexi-Coil Sys. 95 70 ft. Harrow Packer Bar

[edit] References

  1. Harrow. 1911 Encyclopedia. 2008-09-28.
  2. Barlow, Ronald Stokes. 300 Years of Farm Implements and Machinery. Krause Publications: 2003. 38
  3. Harrow. Encyclopedia. 2008-09-28.
  4. Buff, Sheil. Traditional Country Skills. The Lyons Press: 2001. 71
  5. Partridge, Michael. Farm Tools Through the Ages. Osprey: 1973. 78
  6. Partridge, Michael. Farm Tools Through the Ages. Osprey: 1973. 78
  7. Partridge, Michael. Farm Tools Through the Ages. Osprey: 1973. 78
  8. Partridge, Michael. Farm Tools Through the Ages. Osprey: 1973. 78
  9. Grain. 2008-09-28.
  10. Barlow, Ronald Stokes. 300 Years of Farm Implements and Machinery. Krause Publications: 2003. 38
  11. Barlow, Ronald Stokes. 300 Years of Farm Implements and Machinery. Krause Publications: 2003. 38
  12. Spike Tooth Harrow. Britannica. 2008-09-28.
  13. Barlow, Ronald Stokes. 300 Years of Farm Implements and Machinery. Krause Publications: 2003. 38
  14. Harry C. Ramsower, Farm Equipment and How to Use It, pg. 273